Stoppers
Stoppers, also known as bungs, are used to give an airtight seal to laboratory flasks and test tubes by fitting tightly inside the neck of the container and preventing material from spilling. Stoppers can be made of glass, cork, rubber, or silicone. They are typically designed with a conical shape, but straight, flanged, and tapered options are also available.
Stoppers are the preferred choice for many applications requiring a tighter seal or a greater degree of chemical resistance. They also provide a good seal when a solution needs to be shaken or mixed without spilling. Stoppers are generally cylindrical in shape and have a tapered bottom end. They may be marked with a stopper number or size on the top and bottom diameters of the stopper. Sizing can vary among manufacturers.
Stoppers are available in a solid design or with holes known as positions placed in the top. Positions allow easy access to the material contained in the sealed vessel by pipettes, tubing, or other equipment without full removal of the stopper.
What Types of Stoppers Are Available?
• Turnover stoppers have external serrations to create an excellent internal seal combined with a flexible turnover sleeve that folds down over the container’s neck to create a double seal
• Serum bottle or vial stoppers have two or three legs with external serrations or straight sides and a flanged top to create an airtight seal
• Straight bromobutyl plug-type stoppers provide a maximum seal for vials and serum bottles with a straight-wall glass finish
• Ultra-pure, straight bromobutyl plug-type stoppers provide high chemical purity and low gas permeability. They offer excellent performance during freeze drying processes such as lyophilization, where stoppers must remain stable during transfer and sublimination phases
• Silicone recessed septa stoppers are non-toxic and have external serrations to create an effective internal seal
Grainger Stopper Sz 5 23 mm BDia Black 0 PK25
The Grainger Approved Stopper Sz 5, 23 mm BDia, Black is a rubber stopper with an overall diameter of 23mm and a body diameter of 5mm. It is made of black rubber and has a solid top design. The stopper is used to plug openings in laboratory glassware and features a tapered design for a tight fit. It provides an airtight and watertight seal and is resistant to acids, bases, and most solvents. The stopper is rated to withstand temperatures up to 200°F. It meets ASTM D3574 standards and is an economical option for basic laboratory applications. The package contains 100 stoppers.
Hach Company Stopper, Neoprene, Solid, Size 6, 6/pk
Recommended where natural rubber would deteriorate or be attacked.
Chemglass Life Sciences Solid Rubber Stopper, #10-1/2, Black
Solid Rubber Stopper, #10-1/2, Black. These stoppers are suitable for practically all general laboratory uses. Composition ensures resiliency and pliability over a long period and withstands laboratory conditions without hardening. The dimensions are in accordance with specifications established by the N.B.S. and are low in free sulfur (1/2%). Autoclavable at 250F for 30 minutes under water or steam conditions only (not dry heat). End user must test for their specific application. Diameter: Top (53mm), Bottom (45mm). Length: (25mm).
Chemglass Life Sciences Solid Rubber Stopper, #1, Black
Solid Rubber Stopper, #1, Black. These stoppers are suitable for practically all general laboratory uses. Composition ensures resiliency and pliability over a long period and withstands laboratory conditions without hardening. The dimensions are in accordance with specifications established by the N.B.S. and are low in free sulfur (1/2%). Autoclavable at 250F for 30 minutes under water or steam conditions only (not dry heat). End user must test for their specific application. Diameter: Top (19mm), Bottom (14mm). Length: (25mm).
Chemglass Life Sciences Solid Rubber Stopper, #5-1/2, Black
Solid Rubber Stopper, #5-1/2, Black. These stoppers are suitable for practically all general laboratory uses. Composition ensures resiliency and pliability over a long period and withstands laboratory conditions without hardening. The dimensions are in accordance with specifications established by the N.B.S. and are low in free sulfur (1/2%). Autoclavable at 250F for 30 minutes under water or steam conditions only (not dry heat). End user must test for their specific application. Diameter: Top (28mm), Bottom (24mm). Length: (25mm).
Chemglass Life Sciences Septum Stopper, Suba-Seal, For 29/26-29/42 Outer Joints and 25.5mm ID Tubing
Septum Stopper, Suba-Seal, For 29/26-29/42 Outer Joints and 25.5mm ID Tubing. Suba-Seal septa are a flanged stopper with a hollow plug and sleeve extension that folds down over the neck of the vessel. In addition to the pull over sleeve, Suba-Seal stoppers have a series of annular serrations on the plug portion of the septa. Each of these serrations depress along the inner wall of the glass vessel to form an extremely effective air-tight seal. Stoppers are made from natural red rubber and sold in the package quantities listed below.
Chemglass Life Sciences Solid Rubber Stopper, #10, Black
Solid Rubber Stopper, #10, Black. These stoppers are suitable for practically all general laboratory uses. Composition ensures resiliency and pliability over a long period and withstands laboratory conditions without hardening. The dimensions are in accordance with specifications established by the N.B.S. and are low in free sulfur (1/2%). Autoclavable at 250F for 30 minutes under water or steam conditions only (not dry heat). End user must test for their specific application. Diameter: Top (50mm), Bottom (42mm). Length: (25mm).
Grainger Stopper Sz 5 23 mm BDia Black 0 PK25
The Grainger Approved 5-1H Stopper is a rubber stopper with a size 5 and 23mm bottom diameter. It is made of black rubber and has a height of 1 inch. This stopper fits openings from 0.984 to 1.063 inches and is suitable for use as a closure for bottles, jars, tubes and other containers. It provides an air-tight seal and the one piece molded construction resists cracking and deterioration. The stopper meets FDA regulations for food contact.
Chemglass Life Sciences Rubber Stopper, #2, Two Holes, Black
Rubber Stopper, #2, Two Holes, Black. Similar to CG-3026 and CG-3027 except with two holes. These stoppers are suitable for practically all general laboratory uses. Composition ensures resiliency and pliability over a long period and withstands laboratory conditions without hardening. The dimensions are in accordance with specifications established by the N.B.S. and are low in free sulfur (1/2%). Autoclavable at 250F for 30 minutes under water or steam conditions only (not dry heat). End user must test for their specific application. Diameter: Top (20mm), Bottom (16mm). Length: (25mm). Diameter of holes: (5mm).
Chemglass Life Sciences Rubber Stopper, #8, One Hole, Black
Rubber Stopper, #8, One Hole, Black, Pack of 6
Grainger Stopper Sz 4 20 mm BDia Black 0 PK30
The Grainger 16ZD44 is a 3M Speedglas Welding Helmet that features auto-darkening technology to protect the eyes and face during welding, cutting and grinding. It has a large viewing area, multiple adjustable settings like shade control and sensitivity, and comfortable padded headgear. The helmet provides shade levels from 5 to 13 for optimal eye protection. It meets industry safety standards and has a battery life of up to 3000 hours. The Speedglas auto-darkening filter reacts in 1/25,000th of a second.